Printed circuit boards are typically interconnected through a backplane. The backplane may be located at the rear of a cabinet or other housing. The circuit boards are installed in the housing by sliding them into positions that are parallel to each other and perpendicular to the backplane, with their inner edges adjoining the backplane. Electrical connections for routing signals between the boards are formed in part by connectors that attach them to the backplane, and in part by circuitry within the backplane itself. The configuration of that circuitry is constrained by the area and thickness of the backplane. As a result, close proximity of interconnecting traces within the backplane can cause problems such as signal attenuation, signal reflection, crosstalk, impedance discontinuities and noise.